Bonding system

ABSTRACT

A bonding system includes a substrate transfer device configured to transfer a first substrate and a second substrate to a bonding apparatus, a first holding plate configured to hold the first substrate from an upper surface side, and a second holding plate disposed below the first holding plate and configured to hold the second substrate from a lower surface side so that the second substrate faces the first substrate. The substrate transfer device includes a first holding part capable of holding the first substrate from the upper surface side, and a second holding part disposed below the first holding part and capable of holding the second substrate from the lower surface side. The first holding part and the second holding part are configured to receive and hold the first substrate and the second substrate at the same time from the first holding plate and the second holding plate.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority fromJapanese Patent Application No. 2016-137635, filed on Jul. 12, 2016, theentire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a bonding system.

BACKGROUND

In order to meet the demand for higher integration of semiconductordevices, use of a three-dimensional integration technique to stacksemiconductor devices in three dimensions has been proposed. Systemsadopting this three-dimensional integration technique utilize a bondingsystem for bonding substrates such as, e.g., semiconductor wafers(hereinafter referred to as “wafers”) or the like.

Such a bonding system includes a surface modifying apparatus formodifying the surfaces of first and second substrates to be bonded, ahydrophilizing apparatus for hydrophilizing the modified first andsecond substrates, and a bonding apparatus for bonding the hydrophilizedfirst and second substrates by a van der Waals force and hydrogenbonding (an intermolecular force). The bonding system further includes asubstrate transfer device for transferring the first and secondsubstrates between the respective apparatuses.

However, in the substrate transfer device described above, for example,it is configured to receive the processed first and second substratesone at a time from an apparatus for performing a process before bondingand to transfer the first and second substrates to the bondingapparatus. Therefore, in the above-described bonding system, the processof transferring a set of first and second substrates to the bondingapparatus is lengthy.

SUMMARY

Some embodiments of the present disclosure provide a bonding systemcapable of shortening a processing time for transferring first andsecond substrates to a bonding apparatus.

According to one embodiment of the present disclosure, there is provideda bonding system which includes a substrate transfer device configuredto transfer a first substrate and a second substrate to a bondingapparatus for bonding the first substrate and the second substrate, afirst holding plate configured to hold the first substrate from an uppersurface side, and a second holding plate disposed below the firstholding plate and configured to hold the second substrate from a lowersurface side so that the second substrate faces the first substrate. Thesubstrate transfer device includes a first holding part capable ofholding the first substrate from the upper surface side, and a secondholding part disposed below the first holding part and capable ofholding the second substrate from the lower surface side so that thesecond substrate faces the first substrate. Further, the first holdingpart and the second holding part are configured to receive the firstsubstrate held by the first holding plate and the second substrate heldby the second holding plate at the same time from the first holdingplate and the second holding plate, and to hold the first substrate andthe second substrate.

BRIEF DESCRIPTION OF DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate embodiments of the presentdisclosure, and together with the general description given above andthe detailed description of the embodiments given below, serve toexplain the principles of the present disclosure.

FIG. 1 is a schematic plan view showing a configuration of a bondingsystem according to an embodiment.

FIG. 2 is a schematic side view showing the configuration of the bondingsystem according to the embodiment.

FIG. 3 is a schematic side view of a first substrate and a secondsubstrate.

FIG. 4 is a schematic side view showing a configuration of a positionadjusting device.

FIG. 5A is a schematic plan view showing a configuration of an invertingtransition.

FIG. 5B is a schematic side view showing the configuration of theinverting transition.

FIG. 6A is a schematic plan view showing a configuration of a transferdevice.

FIG. 6B is a schematic side view showing the configuration of thetransfer device.

FIG. 7 is a schematic side view showing a configuration of a substratetemperature control device.

FIG. 8A is a view for explaining the operations of the transfer deviceand the substrate temperature control device.

FIG. 8B is a view for explaining the operations of the transfer deviceand the substrate temperature control device.

FIG. 8C is a view for explaining the operations of the transfer deviceand the substrate temperature control device.

FIG. 8D is a view for explaining the operations of the transfer deviceand the substrate temperature control device.

FIG. 8E is a view for explaining the operations of the transfer deviceand the substrate temperature control device.

FIG. 8F is a view for explaining the operations of the transfer deviceand the substrate temperature control device.

FIG. 9 is a view for explaining the detection of positions of an upperwafer and a lower wafer by a position detecting part.

FIG. 10 is a schematic plan view showing a configuration of the bondingapparatus.

FIG. 11 is a schematic side view showing the configuration of thebonding apparatus.

FIG. 12 is a schematic side view showing an internal configuration ofthe bonding apparatus.

FIG. 13 is a schematic side view showing a configuration of an upperchuck and a lower chuck.

FIG. 14 is a schematic plan view of the upper chuck as viewed frombelow.

FIG. 15 is a schematic plan view of the lower chuck as viewed fromabove.

FIG. 16A is an operation explanation view of the bonding apparatus.

FIG. 16B is an operation explanation view of the bonding apparatus.

FIG. 16C is an operation explanation view of the bonding apparatus.

FIG. 16D is an operation explanation view of the bonding apparatus.

FIG. 16E is an operation explanation view of the bonding apparatus.

FIG. 16F is an operation explanation view of the bonding apparatus.

FIG. 16G is an operation explanation view of the bonding apparatus.

FIG. 16H is an operation explanation view of the bonding apparatus.

FIG. 17 is a flowchart showing a part of a processing procedure of aprocess executed by the bonding system.

DETAILED DESCRIPTION

Hereinafter, embodiments of a bonding system disclosed herein will bedescribed in detail with reference to the accompanying drawings. In thefollowing detailed description, numerous specific details are set forthin order to provide a thorough understanding of the present disclosure.However, it will be apparent to one of ordinary skill in the art thatthe present disclosure may be practiced without these specific details.In other instances, well-known methods, procedures, systems, andcomponents have not been described in detail so as not to unnecessarilyobscure aspects of the various embodiments.

<1. Configuration of Bonding System>

First, a configuration of a bonding system according to an embodimentwill be described with reference to FIGS. 1 and 2. FIG. 1 is a schematicplan view showing a configuration of a bonding system according to anembodiment, and FIG. 2 is a schematic side view thereof. Further, FIG. 3is a schematic side view of a first substrate and a second substrate. Inthe following description, in order to clarify the positionalrelationship, an X axis direction, a Y axis direction and a Z axisdirection orthogonal to each other are defined. The Z axis positivedirection is defined as a vertical upward direction. In each of thedrawings including FIGS. 1 to 3, only the components necessary forexplanation are shown, and the illustration of general components may beomitted in some cases.

The bonding system 1 according to this embodiment shown in FIG. 1 isconfigured to form a laminated substrate T by bonding a first substrateW1 and a second substrate W2 (see FIG. 3).

The first substrate W1 is, for example, a substrate in which a pluralityof electronic circuits is formed on a semiconductor substrate such as asilicon wafer or a compound semiconductor wafer. The second substrate W2is, for example, a bare wafer in which no electronic circuit is formed.The first substrate W1 and the second substrate W2 have approximatelythe same diameter.

An electronic circuit may be formed on the second substrate W2. As theaforementioned compound semiconductor wafer, it may be possible to use,for example, a wafer which contains gallium arsenide, silicon carbide,gallium nitride, indium phosphide or the like. However, the presentdisclosure is not limited thereto.

In the following description, the first substrate W1 may be referred toas “upper wafer W1”, the second substrate W2 may be referred to as“lower wafer W2”, and the laminated substrate T may be referred to as“laminated wafer T.”

In the following description, as shown in FIG. 3, the substrate surfaceof the upper wafer W1 to be bonded to the lower wafer W2 will bereferred to as “bonding surface W1 j” and the substrate surface on theside opposite to the bonding surface W1 j will be referred to as“non-bonding surface W1 n.” Likewise, the substrate surface of the lowerwafer W2 to be bonded to the upper wafer W1 will be referred to as“bonding surface W2 j” and the substrate surface on the side opposite tothe bonding surface W2 j will be referred to as “non-bonding surface W2n.”

As shown in FIG. 1, the bonding system 1 includes a loading/unloadingstation 2 and a processing station 3. The loading/unloading station 2and the processing station 3 are arranged side by side in the order ofthe loading/unloading station 2 and the processing station 3 along the Xaxis positive direction. The loading/unloading station 2 and theprocessing station 3 are integrally connected to each other.

The loading/unloading station 2 includes a mounting table 10 and atransfer region 20. The mounting table 10 includes a plurality ofmounting plates 11. On the respective mounting plates 11, cassettes C1,C2 and C3 for accommodating a plurality of substrates (for example, 25substrates) in a horizontal state are mounted, respectively. Thecassette C is a cassette for accommodating the upper wafer W1, thecassette C2 is a cassette for accommodating the lower wafer W2, and thecassette C3 is a cassette for accommodating the laminated wafer T. Inthe cassettes C1 and C2, the upper wafer W1 and the lower wafer W2 areaccommodated with their orientations aligned such that the bondingsurfaces W1 j and W2 j face upward.

The transfer region 20 is disposed adjacent to the mounting table 10 onthe side of the X axis positive direction. In the transfer region 20, atransfer path 21 extending in the Y axis direction and a transfer device22 movable along the transfer path 21 are provided. The transfer device22 is also movable in the X axis direction and is rotatable around the Zaxis. The transfer device 22 transfers the upper wafer W1, the lowerwafer W2 and the laminated wafer T between the cassettes C1 to C3mounted on the mounting plates and the third processing block G3 of theprocessing station 3 to be described later.

The number of cassettes C1 to C3 mounted on the mounting plates 11 isnot limited to that shown in the drawings. In addition to the cassettesC1, C2 and C3, a cassette for recovering a defective substrate or thelike may be mounted on the mounting plates 11.

In the processing station 3, a plurality of, for example, three,processing blocks G1, G2 and G3 having various apparatuses are provided.For example, a first processing block G1 is provided on the rear side ofthe processing station 3 (on the side of the Y axis positive directionin FIG. 1), and a second processing block G2 is provided on the frontside of the processing station 3 (the side of the Y axis negativedirection in FIG. 1). A third processing block G3 is provided on theloading/unloading station 2 side (on the side of the X axis negativedirection in FIG. 1) of the processing station 3.

In a region surrounded by the first processing block G1 to the thirdprocessing block G3, a transfer region 60 is formed. In the transferregion 60, a transfer device 61 is disposed. The transfer device 61includes a transfer arm which is movable in the vertical direction andthe horizontal direction and rotatable around the vertical axis. Thetransfer device 61 is configured to be able to receive the upper waferW1 and the lower wafer W2 held by a below-described substratetemperature control device 42 at the same time. A detailed configurationof the transfer device 61 will be described later with reference toFIGS. 6A and 6B.

The transfer device 61 moves within the transfer region 60 and transfersthe upper wafer W1, the lower wafer W2 and the laminated wafer T topredetermined apparatuses disposed in the first processing block G1, thesecond processing block G2 and the third processing block G3 adjacent tothe transfer region 60.

In this regard, the transfer of the upper wafer W1, the lower wafer W2and the laminated wafer T by the transfer device 61 is performed in anormal pressure atmosphere. The normal pressure is, for example, anatmospheric pressure. However, the normal pressure does not need to beexactly the same as the atmospheric pressure and may include a pressurerange of, for example, ±10 kPa with respect to the atmospheric pressure.In addition, the transfer device 61 is an example of a substratetransfer device.

In the first processing block G1, a load lock chamber 31, a transferchamber 32, a surface modifying apparatus 33 and a surfacehydrophilizing apparatus 34 (see FIG. 2) are disposed.

The load lock chamber 31 is located at a position most distant from theloading/unloading station 2 in the first processing block G1 and isdisposed adjacent to the Y axis positive direction side of the transferregion 60 via a gate valve 36 a. The transfer chamber 32 is disposedadjacent to the X axis negative direction side of the load lock chamber31 via a gate valve 36 b, and the surface modifying apparatus 33 islocated at a position closest to the loading/unloading station 2 in thefirst processing block G1 and is disposed adjacent to the X axisnegative direction side of the transfer chamber 32 via a gate valve 36c.

In the load lock chamber 31, the upper wafer W1 and the lower wafer W2are delivered between the transfer device 61 and the surface modifyingapparatus 33. Specifically, a plurality of transitions 31 a 1 and 31 a 2is provided inside the load lock chamber 31 (see FIG. 2). Thetransitions 31 a 1 and 31 a 2 are configured to mount the upper wafer W1or the lower wafer W2. In this embodiment, for example, the transition31 a 1 mounts the upper wafer W1 or the lower wafer W2 loaded from thetransfer device 61 into the surface modifying apparatus 33, and thetransition 31 a 2 mounts the upper wafer W1 or the lower wafer W2unloaded from the surface modifying apparatus 33 to the transfer device61.

As shown in FIG. 2, the transitions 31 a 1 and 31 a 2 are stacked anddisposed in the vertical direction. However, the present disclosure isnot limited thereto. For example, the transitions 31 a 1 and 31 a 2 maybe disposed so as to be adjacent to each other in a plan view. Thetransitions 31 a 1 and 31 a 2 are an example of a substrate mountingtable.

A vacuum pump 31 c (see FIG. 2) is connected to the load lock chamber 31via a suction pipe 31 b. Thus, for example, when the gate valves 36 aand 36 b are closed and when the vacuum pump 31 c is operated, theinterior of the load lock chamber 31 is depressurized into adepressurized atmosphere. On the other hand, for example, when the gatevalve 36 a is opened, the interior of the load lock chamber 31communicates with the transfer region 60 whose interior is kept under anatmospheric pressure atmosphere. Thus, the atmosphere in the load lockchamber 31 becomes an atmospheric pressure atmosphere. As describedabove, the load lock chamber 31 is configured so that the atmosphere inthe load lock chamber 31 can be switched between the atmosphericpressure atmosphere and the depressurized atmosphere.

In the transfer chamber 32, a transfer device for surface modifyingapparatus (hereinafter referred to as “modifying transfer device”) 32 ais disposed. The modifying transfer device 32 a includes, for example, atransfer arm which is movable in the vertical direction and thehorizontal direction and rotatable around the vertical axis. Themodifying transfer device 32 a receives, for example, the unmodifiedupper wafer W1 or the like mounted on the transition 31 a 1 of the loadlock chamber 31 and transfers the unmodified upper wafer W1 to thesurface modifying apparatus 33. Furthermore, the modifying transferdevice 32 a transfers the upper wafer W1 or the like modified in thesurface modifying apparatus 33 to the load lock chamber 31 andmounts/places the upper wafer W1 or the like on the transition 31 a 2(see FIG. 2).

A vacuum pump 32 c (see FIG. 2) is connected to the transfer chamber 32via a suction pipe 32 b. When the vacuum pump 32 c is operated, theinterior of the transfer chamber 32 is depressurized into adepressurized atmosphere. The gate valve 36 b is opened when the loadlock chamber 31 is in the depressurized atmosphere. Similarly, the gatevalve 36 c is opened when the surface modifying apparatus 33 is in thedepressurized atmosphere.

Therefore, the transfer chamber 32 is constantly kept under thedepressurized atmosphere by the vacuum pump 32 c. In this way, themodifying transfer device 32 a of the transfer chamber 32 is disposedadjacent to the load lock chamber 31 and is configured to transfer theupper wafer W1 and the lower wafer W2 between the load lock chamber 31and the surface modifying apparatus 33 under the depressurizedatmosphere.

The surface modifying apparatus 33 is configured to modify the bondingsurfaces W1 j and W2 j of the upper wafer W1 and the lower wafer W2. Avacuum pump 33 c (see FIG. 2) is connected to the surface modifyingapparatus 33 via a suction pipe 33 b. When the vacuum pump 33 c isoperated, the interior of the surface modifying apparatus 33 isdepressurized into a depressurized atmosphere. As with the transferchamber 32, the surface modifying apparatus 33 is also constantly keptin the depressurized atmosphere.

Therefore, the surface modifying apparatus 33 modifies the bondingsurfaces W1 j and W2 j of the upper wafer W1 and the lower wafer W2under the depressurized atmosphere. More specifically, the surfacemodifying apparatus 33 breaks the bonds of SiO₂ on the bonding surfacesW1 j and W2 j of the upper wafer W1 and the lower wafer W2 to formsingle-bond SiO₂, thereby modifying the bonding surfaces W1 j and W2 jso that the bonding surfaces W1 j and W2 j can be subsequentlyhydrophilized with ease.

In the surface modifying apparatus 33, an oxygen gas, which is a processgas, is excited into plasma under a processing apparatus and is ionized.Then, the bonding surfaces W1 j and W2 j of the upper wafer W1 and thelower wafer W2 are irradiated with the oxygen ions, whereby the bondingsurfaces W1 j and W2 j are subjected to plasma treatment and aremodified.

The internal volume of the load lock chamber 31 described above is setto become smaller than the internal volume of the surface modifyingapparatus 33 or the transfer chamber 32. However, the present disclosureis not limited thereto.

Now, the transfer of the upper wafer W1 in the load lock chamber 31, thetransfer chamber 32 and the surface modifying apparatus 33 configured asabove will be described in detail. Since the lower wafer W2 istransferred in the same manner as the upper wafer W1, the followingdescription is also generally applicable to the transfer of the lowerwafer W2. It is assumed that the gate valves 36 a. 36 b and 36 c are allclosed.

Specifically, first, when the unmodified upper wafer W1 is transferredto the front of the load lock chamber 31 by the transfer device 61, thegate valve 36 a is opened and the unmodified upper wafer W1 is mountedon the transition 31 a 1 of the load lock chamber 31. In addition, whenthe unmodified upper wafer W1 is mounted on the transition 31 a 1, theremay be a case where the upper wafer W1 or the lower wafer W2 alreadymodified in the previous process is mounted on the transition 31 a 2. Insuch a case, after mounting the unmodified upper wafer W1 on thetransition 31 a 1, the transfer device 61 may receive the upper wafer W1or the lower wafer W2 mounted on the transition 31 a 2 and may removethe upper wafer W1 or the lower wafer W2 from the load lock chamber 31.

Next, the gate valve 36 a is closed, the vacuum pump 31 c is operated,and the load lock chamber 31 is depressurized into a depressurizedatmosphere.

Next, the gate valves 36 b and 36 c are opened, and the modifyingtransfer device 32 a transfers the upper wafer W1 mounted on thetransition 31 a 1 to the surface modifying apparatus 33. Subsequently,the gate valves 36 b and 36 c are closed, and the modifying process ofthe upper wafer W1 is performed by the surface modifying apparatus 33.

When the modifying process is completed, the gate valves 36 b and 36 care opened. The modifying transfer device 32 a takes out the upper waferW1 from the surface modifying apparatus 33 and transfers the upper waferW1 to the transition 31 a 2 of the load lock chamber 31. Next, after thegate valves 36 b and 36 c are closed, the gate valve 36 a is opened sothat the internal atmosphere of the load lock chamber 31 is switchedfrom the depressurized atmosphere to the atmospheric pressureatmosphere.

Then, the transfer device 61 takes out the modified upper wafer W1 fromthe transition 31 a 2 of the load lock chamber 31 and transfers themodified upper wafer W1 to the surface hydrophilizing apparatus 34 wherethe next process is performed.

As described above, the bonding system 1 according to the presentembodiment includes the load lock chamber 31 in which the upper wafer W1and the lower wafer W2 are delivered between the transfer device 61 andthe surface modifying apparatus 33 and in which the atmosphere can beswitched between the atmospheric pressure atmosphere and thedepressurized atmosphere.

Thus, in the bonding system 1, it is possible to shorten the processingtime of the upper wafer W1 and the lower wafer W2. That is to say, whenthe upper wafer W1 and the lower wafer W2 are loaded and unloaded to andfrom the surface modifying apparatus 33, if the internal pressure of theload lock chamber 31 is made switchable, it is possible for the surfacemodifying apparatus 33 to carry out the modifying process whilemaintaining the depressurized atmosphere. Accordingly, in the surfacemodifying apparatus 33, the process of switching the atmosphericpressure atmosphere to the depressurized atmosphere is not required.This makes it possible to shorten the time required for the modifyingprocess of the upper wafer W1 and the lower wafer W2.

The internal volume of the load lock chamber 31 is set to become smallerthan the internal volume of the surface modifying apparatus 33 or thetransfer chamber 32. This makes it possible to shorten the time requiredfor switching the internal pressure of the load lock chamber 31 ascompared with the time required for switching the internal pressure ofthe surface modifying apparatus 33.

Furthermore, the modifying transfer device 32 a is not disposed in theload lock chamber 31 but is disposed adjacent to the load lock chamber31. Thus, the load lock chamber 31 can be reduced in size as comparedwith the case where the modifying transfer device 32 a is disposed inthe load lock chamber 31. As a result, it is possible to further shortenthe time required for switching the internal pressure of the load lockchamber 31.

The surface hydrophilizing apparatus 34 (see FIG. 2) hydrophilizes andcleans the bonding surfaces W1 j and W2 j of the upper wafer W1 and thelower wafer W2 by a hydrophilization treatment liquid such as, forexample, pure water or the like. In the surface hydrophilizing apparatus34, for example, pure water is supplied onto the upper wafer W1 or thelower wafer W2 while rotating the upper wafer W1 or the lower wafer W2held by a spin chuck. As a result, the pure water supplied onto theupper wafer W1 or the lower wafer W2 diffuses on the bonding surface W1j or W2 j of the upper wafer W1 or the lower wafer W2, whereby thebonding surface W1 j or W2 j is made hydrophilic.

As shown in FIG. 2, in the first processing block G1, the load lockchamber 31, the transfer chamber 32, the surface modifying apparatus 33and the surface hydrophilizing apparatus 34 are disposed in a stackedstate. More specifically, for example, in the first processing block G1,the load lock chamber 31, the transfer chamber 32 and the surfacemodifying apparatus 33 are disposed in the lower stage on the Z axisnegative direction side, while the surface hydrophilizing apparatus 34is disposed in the upper stage on the Z axis positive direction side.

As described above, in this embodiment, the load lock chamber 31, thetransfer chamber 32 and the surface modifying apparatus 33 are disposedbelow the surface hydrophilizing apparatus 34. Thus, for example, thevacuum pumps 31 c, 32 c and 33 c and the suction pipes 31 b, 32 b and 33b connected to the load lock chamber 31, the transfer chamber 32 and thesurface modifying apparatus 33 can be collectively disposed below thebonding system 1. This makes it possible to downsize the entire system.

Furthermore, the vacuum pumps 31 c, 32 c and 33 c are disposed in thevicinity of the load lock chamber 31, the transfer chamber 32 and thesurface modifying apparatus 33. It is therefore possible to shorten thesuction pipes 31 b, 32 b and 33 b, eventually minimizing the timerequired for depressurization.

The arrangement positions of the load lock chamber 31, the surfacemodifying apparatus 33 and the surface hydrophilizing apparatus 34 shownin FIG. 1 are illustrative and not limitative. That is to say, the loadlock chamber 31 and the surface modifying apparatus 33 may be disposedabove the surface hydrophilizing apparatus 34. Furthermore, for example,the load lock chamber 31 and the surface modifying apparatus 33 may bedisposed in the second processing block G2 or the third processing blockG3. Moreover, for example, a new station may be provided at a positionon the X axis positive direction side of the processing station 3 orbetween the loading/unloading station 2 and the processing station 3.The load lock chamber 31 and the surface modifying apparatus 33 may bedisposed in the new station.

In the second processing block G2, a bonding apparatus 41, a substratetemperature control device 42 and an exhaust port 43 are disposed. Thebonding apparatus 41 is located at a position closest to theloading/unloading station 2 in the second processing block G2. Thesubstrate temperature control device 42 is disposed adjacent to thebonding apparatus 41 on the X axis positive direction side thereof. Thesubstrate temperature control device 42 is disposed adjacent to theexhaust port 43 on the X axis negative direction side thereof.

The bonding apparatus 41 bonds the hydrophilized upper wafer W1 and thehydrophilized lower wafer W2 by an intermolecular force. The detailedconfiguration of the bonding apparatus 41 will be described later withreference to FIGS. 10 to 16H.

The substrate temperature control device 42 controls the temperature ofthe upper wafer W1 before bonding and the temperature of the lower waferW2 before bonding, respectively. The detailed configuration of thesubstrate temperature control device 42 will be described later withreference to FIG. 7.

The exhaust port 43 discharges a temperature control gas (hereinafterreferred to as “temperature control air”). That is to say, although notshown in the drawings, the processing station 3 is provided with an airsupply port which is disposed at an appropriate position such as, forexample, a ceiling portion on the side of the loading/unloading station2 or the like so as to supply the temperature control air. The exhaustport 43 is configured to discharge the temperature control air suppliedfrom the air supply port and passing through the processing station 3 tothe outside of the processing station 3.

Therefore, in the processing station 3, the bonding apparatus 41, thesubstrate temperature control device 42 and the exhaust port 43 aredisposed in this order along the flow direction of the temperaturecontrol air (the X axis positive direction). In other words, thesubstrate temperature control device 42 is disposed on the downstreamside of the bonding apparatus 41 in the flow direction of thetemperature control air.

The arrangement position of the exhaust port 43 is not limited to theexample shown in the drawing. The exhaust port 43 may be disposed atother positions, for example, in the vicinity of the load lock chamber31 or in the vicinity of the transfer region 60. Furthermore, theposition of the air supply port is not limited to the one describedabove. The air supply port may be disposed at other positions such as afloor portion or a wall portion of the processing station 3.

As shown in FIG. 2, in the third processing block G3, a positionadjusting device 51, transitions 53 and 54, and an inverting transition55 are stacked and arranged sequentially from the upper side. Thearrangement locations of the respective devices in the third processingblock G3 are merely illustrative and not limitative.

FIG. 4 is a schematic side view showing a configuration of the positionadjusting device 51. The position adjusting device 51 adjusts thehorizontal orientations of the upper wafer W1 and the lower wafer W2. Asshown in FIG. 4, the position adjusting device 51 includes a base 51 a,a holding part 51 b configured to suck, hold and rotate the upper waferW1 and the lower wafer W2, a detecting part 51 c configured to detect aposition of a notch portion of each of the upper wafer W1 and the lowerwafer W2, and a base inverting part 51 d configured to invert the base51 a.

In the position adjusting device 51, the position of the notch portionof each of the upper wafer W1 and the lower wafer W2 is detected by thedetecting part 51 c while rotating the upper wafer W1 and the lowerwafer W2 sucked and held by the holding part 51 b, whereby thehorizontal orientations of the upper wafer W1 and the lower wafer W2 areadjusted by adjusting the positions of the notch portions.

In the detecting part 51 c, for example, a camera (not shown) may beprovided so as to capture images of the peripheral edges of the upperwafer W1 and the lower wafer W2. For example, the detecting part 51 ccaptures an image of the peripheral edge of the upper wafer W1 or thelike while rotating the upper wafer W1 or the like held by the holdingpart 51 b by one rotation, and plots the peripheral edge of the upperwafer W1 or the like based on the captured image. The detecting part 51c may detect the radius of the upper wafer W1 and the lower wafer W2based on the information on the peripheral edge of the upper wafer W1 orthe like thus plotted.

In this manner, the position adjusting device 51 also functions as aradius detecting device for detecting the radius of the upper wafer W1and the lower wafer W2. In the above description, the radius of theupper wafer W1 or the like is detected by the position adjusting device51. However, the present disclosure is not limited thereto. For example,identification information (ID) indicating the radius or the like may beattached to the upper wafer W1 or the like. The radius may be detectedby reading such identification information.

The base inverting part 51 d includes, for example, a motor and thelike. The base inverting part 51 d is connected to the base 51 a and isconfigured to invert the base 51 a for each upper wafer W1 held by theholding part 51 b. Thus, the front and back surfaces of the upper waferW1 held by the holding part 51 b are inverted. Accordingly, for example,the upper wafer W1 whose horizontal orientation is adjusted comes into astate in which the bonding surface W1 j serves as a lower surface (seeFIG. 2) by the above-described inversion. In this state, the upper waferW1 is unloaded from the position adjusting device 51. The upper wafer W1and the lower wafer W2 unloaded from the position adjusting device 51are transferred to the substrate temperature control device 42 and aretemperature-controlled.

Returning to the description of FIG. 2, the upper wafer W1 transferredby the transfer device 22 or the transfer device 61 is temporarilymounted on the transition 53. Furthermore, the lower wafer W2 or thelaminated wafer T transferred by the transfer device 22 or the transferdevice 61 is temporarily mounted on the transition 54.

The inverting transition 55 is a device configured to temporarily holdthe upper wafer W1 or the lower wafer W2 not bonded in the bondingapparatus 41 for a certain reason and returned from the bondingapparatus 41 in a state in which the bonding surface W1 j or W2 j servesas a lower surface. The inverting transition 55 is an example of asubstrate transfer device.

FIG. 5A is a schematic plan view showing the configuration of theinverting transition 55, and FIG. 5B is a schematic side view showingthe configuration of the inverting transition 55. As shown in FIG. 5B,the inverting transition 55 includes a holding part 56 and an invertingmechanism 57. The holding part 56 holds, on the side of a lower surface56 a 1 thereof, the upper wafer W1 or the lower wafer W2 having thebonding surface W1 j or W2 j as a lower surface.

Specifically, the holding part 56 is provided with a suction portion 56a 2 on the side of a lower surface 56 a 1 thereof. A vacuum pump 56 a 4is connected to the suction portion 56 a 2 via a suction pipe 56 a 3.Therefore, the lower surface 56 a 1 of the holding part 56 holds theupper wafer W1 or the lower wafer W2 through vacuum suction by theoperation of the vacuum pump 56 a 4. As a result, the holding part 56can reliably hold the upper wafer W1 and the like.

The holding part 56 is further provided with a suction portion 56 b 2 onthe side of an upper surface 56 b 1 thereof. A vacuum pump 56 b 4 isconnected to the suction portion 56 b 2 via a suction pipe 56 b 3.Therefore, the upper surface 56 b 1 of the holding part 56 is configuredto be able to suck the upper wafer W1 or the like by the operation ofthe vacuum pump 56 b 4.

The inverting mechanism 57 includes, for example, a motor and the like.The inverting mechanism 57 is connected to the holding part 56 and isconfigured to invert the front and back surfaces of the upper wafer W1or the like held by the holding part 56. The inverting mechanism 57 ofthe inverting transition 55 inverts the upper wafer W1 not bonded by thebonding apparatus 41.

Specifically, for example, there may be a case where, for some reason,the upper wafer W1 and the lower wafer W2 are not bonded in the bondingapparatus 41, and the upper wafer W1 having the bonding surface W1 j asa lower surface is returned to the third processing block G3. In thiscase, the upper wafer W1 having the bonding surface W1 j as a lowersurface is transferred to the inverting transition 55 by the transferdevice 61 and is held by the suction portion 56 a 2 from the side of thenon-bonding surface W1 n. Next, the inverting mechanism 57 inverts theholding part 56 so that the upper wafer W1 is brought into a state inwhich the bonding surface W1 j serves as an upper surface. The upperwafer W1 in such a state is indicated by imaginary lines in FIGS. 5A and5B.

Thus, for example, the upper wafer W1 returned without being bonded inthe bonding apparatus 41 can be brought into the same state as when theupper wafer W1 is accommodated in the cassette C1, namely a state inwhich the bonding surface W1 j serves as an upper surface as indicatedby an imaginary line in FIG. 5B. In this manner, in the invertingtransition 55, for example, it is possible to easily invert the frontand back surfaces of the upper wafer W1 having the bonding surface W1 jas a lower surface. The upper wafer W1 having the bonding surface W1 jas an upper surface can be transferred to the cassette C1 by thetransfer device 22 and can be accommodated in the cassette C1 as it is.

Next, the configuration of the transfer device 61 will be described withreference to FIGS. 6A and 6B. FIG. 6A is a schematic plan view showingthe configuration of the transfer device 61, and FIG. 6B is a schematicside view showing the configuration of the transfer device 61.

As shown in FIG. 6B, the transfer device 61 includes a first holdingpart 62 a, a second holding part 62 b provided to face the lower side ofthe first holding part 62 a, and a first driving part 64. As the firstholding part 62 a and the second holding part 62 b, it may be possibleto use a bifurcated fork whose lateral width is smaller than thediameter of the upper wafer W1 or the like. However, the presentdisclosure is not limited thereto.

In this embodiment, the first holding part 62 a is used for holding theupper wafer W1 having the bonding surface W1 j as a lower surface. Onthe other hand, the second holding part 62 b is used for holding thelower wafer W2 having the bonding surface W2 j as an upper surface, theupper wafer W1 having the bonding surface W1 j as an upper surface, thelaminated wafer T, and the like. The types of the respective wafers heldby the first holding part 62 a and the second holding part 62 b areillustrative and not limitative. For example, the first holding part 62a may hold the laminated wafer T.

In the first holding part 62 a, a plurality of suction portions 62 a 2(indicated by broken lines in FIG. 6A) is provided on the side of alower surface 62 a 1 thereof. A vacuum pump 62 a 4 is connected to thesuction portions 62 a 2 via a suction pipe 62 a 3. Therefore, the firstholding part 62 a holds the upper wafer W1 through vacuum suction by theoperation of the vacuum pump 62 a 4. Specifically, the first holdingpart 62 a holds the upper wafer W1 having the bonding surface W1 j as alower surface from the side of the non-bonding surface W1 n (uppersurface side) by vacuum suction.

The second holding part 62 b includes a plurality of suction portions(not visible in FIGS. 6A and 6B) on the side of an upper surface 62 b 1.A vacuum pump 62 b 4 is connected to the suction portions via a suctionpipe 62 b 3 (see FIG. 6B). Therefore, the second holding part 62 b holdsthe lower wafer W2 or the like through vacuum suction by the operationof the vacuum pump 62 b 4.

Specifically, the second holding part 62 b holds the lower wafer W2having the bonding surface W2 j as an upper surface through vacuumsuction from the side of the non-bonding surface W2 n (lower surfaceside) by allowing the lower wafer W2 to face the upper wafer W1.Although not shown, the second holding part 62 b also holds thelaminated wafer T by vacuum suction as described above.

In this manner, the first holding part 62 a holds the upper wafer W1 byvacuum suction, and the second holding part 62 b holds the lower waferW2 by vacuum suction. Thus, the first and second holding parts 62 a and62 b can reliably hold the upper wafer W1 and the lower wafer W2.

The first driving part 64 is connected to the first holding part 62 aand the second holding part 62 b. The first driving part 64 drives thefirst holding part 62 a and the second holding part 62 b together andintegrally moves the first holding part 62 a and the second holding part62 b in the vertical direction and the horizontal direction and aboutthe vertical axis with respect to a base 65. Although not shown, thefirst driving part 64 includes a drive source such as a motor or thelike and a power transmission mechanism such as a belt or the like.

By configuring the transfer device 61 as described above, it is possibleto downsize the transfer device 61. That is to say, for example, ifdriving parts are respectively connected to the first holding part 62 aand the second holding part 62 b, the number of driving parts is two andthe transfer device 61 is increased in size. However, in the transferdevice 61 according to the present embodiment, the first and secondholding parts 62 a and 62 b are driven together by one first drivingpart 64. This makes it possible to reduce the size of the transferdevice 61.

When transferring the upper wafer W1 and the lower wafer W2 to thebonding apparatus 41, the transfer device 61 holds the upper wafer W1with the first holding part 62 a and holds the lower wafer W2 with thesecond holding part 62 b, thereby transferring the upper wafer W1 andthe lower wafer W2 together.

More specifically, the first holding part 62 a holds the upper wafer W1having the bonding surface W1 j as a lower surface from the uppersurface side, and the second holding part 62 b holds the lower wafer W2having the bonding surface W2 j as an upper surface from the lowersurface side by allowing the lower wafer W2 to face the upper wafer W1.

Thus, in the bonding apparatus 41, the upper wafer W1 and the lowerwafer W2 are transferred in the same orientation as that available whenperforming a bonding process. Therefore, in the bonding apparatus 41, itis not necessary to perform, for example, a process of inverting theorientation of the upper wafer W1. As a result, it is possible toshorten the time required for performing the bonding process in thebonding apparatus 41. In this embodiment, the second holding part 62 btransfers the lower wafer W2 to the bonding apparatus 41 while holdingthe lower wafer W2 in a state in which the center thereof is shiftedfrom the center of the upper wafer W1. This will be described later withreference to FIGS. 8A to 9.

The transfer device 61 further includes a plurality of (four, in thisexample) position detecting parts 70 a to 70 d. For example, theposition detecting parts 70 a to 70 d are fixed to the base 65. Theposition detecting parts 70 a to 70 d detect the positions of theperipheral edges of the upper wafer W1 and the lower wafer W2 held bythe first holding part 62 a and the second holding part 62 b, atdifferent locations, respectively.

More specifically, each of the position detecting parts 70 a to 70 dincludes a light projecting part 71 and a light receiving part 72. Thelight projecting part 71 and the light receiving part 72 are disposed atpositions where the light projecting part 71 and the light receivingpart 72 sandwich the upper wafer W1 and the lower wafer W2 held by thefirst holding part 62 a and the second holding part 62 b from above andbelow. That is, the position detecting parts 70 a to 70 d are disposedperpendicularly to the surfaces (for example, the bonding surfaces W jand W2 j and the non-bonding surfaces Win and W2 n) of the upper waferW1 and the lower wafer W2 held by the first holding part 62 a and thesecond holding part 62 b

The arrangement of the light projecting part 71 and the light receivingpart 72 is not limited to the example described above. For example, thelight projecting part 71 may be disposed above the upper wafer W1 or thelike and the light receiving part 72 may be disposed below the upperwafer W1 or the like. As the light receiving part 72, it may be possibleto use a line sensor in which a plurality of light receiving elements islinearly arranged. However, the present disclosure is not limitedthereto.

The light receiving part 72 receives the light irradiated from the lightprojecting part 71 using the light receiving elements. However, when theupper wafer W1 or the like exists between the light projecting part 71and the light receiving part 72, the light is partially blocked by theupper wafer W1 or the like.

As a result, in the light receiving part 72, a difference occurs in theamount of received light between the light receiving element thatreceives light and the light receiving element that does not receivelight. The position detecting parts 70 a to 70 d detect the position ofthe peripheral edge of the upper wafer W1 or the like based on thedifference in the amount of received light. The position detecting parts70 a to 70 d send a signal indicating the detection result to a controldevice 100 (see FIG. 1) which will be described later. A process fordetecting the position of the peripheral edge of the upper wafer W1 orthe like by the position detecting parts 70 a to 70 d will be describedlater.

Returning to the description of FIG. 1, the bonding system 1 includes acontrol device 100. The control device 100 controls the operation of thebonding system 1. The control device 100 is, for example, a computer,and includes a control part and a memory unit (not shown). A program forcontrolling various processes such as a bonding process and the like,data used in various processes, and the like are stored in the memorypart. The control part controls the operation of the bonding system 1 byreading out and executing the program or the like stored in the memorypart.

Such a program may be recorded in a computer-readable recording mediumand may be installed in the memory part of the control device 100 fromthe recording medium. Examples of the computer-readable recording mediuminclude a hard disk (HD), a flexible disk (FD), a compact disk (CD), amagneto-optical disk (MO), a memory card, and the like.

Now, the substrate temperature control device 42 will be described indetail with reference to FIG. 7. FIG. 7 is a schematic side view showingthe configuration of the substrate temperature control device 42.

The upper wafer W1 having the bonding surface W1 j as a lower surfaceand the lower wafer W2 having the bonding surface W2 j as an uppersurface are transferred to the substrate temperature control device 42by the transfer device 61. The substrate temperature control device 42controls the temperature of each of the upper wafer W1 and the lowerwafer. Specifically, as shown in FIG. 7, the substrate temperaturecontrol device 42 includes a first temperature control holding plate 42a and a second temperature control holding plate 42 b. The firsttemperature control holding plate 42 a is an example of a first holdingplate, and the second temperature control holding plate 42 b is anexample of a second holding plate.

The first temperature control holding plate 42 a holds the upper waferW1 before bonding, more specifically, the upper wafer W1 afterhydrophilizing and before bonding. Specifically, the first temperaturecontrol holding plate 42 a is provided with a plurality of holding pins42 a 2 on a holding surface 42 a 1 for holding the upper wafer W1. Theholding pins 42 a 2 are configured to be movable upward and downwardwith respect to the holding surface 42 a 1 of the first temperaturecontrol holding plate 42 a.

A vacuum pump 42 a 4 is connected to the holding pins 42 a 2 via asuction pipe 42 a 3. Therefore, the first temperature control holdingplate 42 a holds the upper wafer W1 through vacuum suction by theoperation of the vacuum pump 42 a 4. It is assumed that the non-bondingsurface W1 n of the upper wafer W1 is sucked and held by the holdingpins 42 a 2 of the first temperature control holding plate 42 a.

Furthermore, a first temperature control mechanism 42 a 5 is built inthe first temperature control holding plate 42 a. For example, atemperature-controlled coolant such as cooling water or the like iscirculated through the first temperature control mechanism 42 a 5.Accordingly, the first temperature control holding plate 42 a controlsthe temperature of the upper wafer W1 by adjusting the coolingtemperature of the first temperature control mechanism 42 a 5 or byraising and lowering the holding pins 42 a 2 to adjust the spaced-apartdistance between the holding pins 42 a 2 and the upper wafer W1.

As shown in FIG. 7, the second temperature control holding plate 42 b isdisposed to hold the lower wafer W2 in a state in which the centerthereof is shifted from the center of the upper wafer W1 held by thefirst temperature control holding plate 42 a.

Specifically, the second temperature control holding plate 42 b isdisposed so that a holding surface 42 b 1 thereof faces the holdingsurface 42 a 1 of the first temperature control holding plate 42 a. Thesecond temperature control holding plate 42 b holds the lower wafer W2before bonding, specifically the lower wafer W2 after hydrophilizing andbefore bonding, from the lower surface side so that the lower wafer W2faces the upper wafer W1.

At this time, as shown in FIG. 7, in the lower wafer W2 held by thesecond temperature control holding plate 42 b, the center W2 c thereofis shifted from the center W1 c of the upper wafer W1 by a predetermineddistance E in the Y axis positive direction.

The predetermined distance E is, for example, about several mm toseveral tens of mm, but is not limited thereto. Further, in theillustrated example, the lower wafer W2 held by the second temperaturecontrol holding plate 42 b is positioned so as to be shifted from theupper wafer W1 in the Y axis direction. However, this is illustrativeand not limitative. For example, the lower wafer W2 may be positioned soas to be shifted from the upper wafer W1 in the X axis direction orother directions.

Furthermore, the second temperature control holding plate 42 b isprovided with a plurality of holding pins 42 b 2 on the holding surface42 b 1 for holding the lower wafer W2. The holding pins 42 b 2 areconfigured to be movable upward and downward with respect to the holdingsurface 42 b 1 of the second temperature control holding plate 42 b.

A vacuum pump 42 b 4 is connected to the holding pins 42 b 2 via asuction pipe 42 b 3. Therefore, the second temperature control holdingplate 42 b holds the lower wafer W2 using vacuum suction from the vacuumpump 42 b 4.

Thus, the second temperature control holding plate 42 b can reliablyhold the lower wafer W2. That is to say, for example, in the secondtemperature control holding plate 42 b, when the holding pins 42 b 2hold the lower wafer W2 by mounting instead of vacuum suction, a stoppermember for preventing the lower wafer W2 from sliding down is providedon the holding surface 42 b 1 at a position corresponding to the radialsize of the lower wafer W2. However, in the second temperature controlholding plate 42 b according to this embodiment, vacuum suction isperformed as described above. Therefore, there is no need to use astopper member to prevent slippage. It is possible to reliably hold thelower wafer W2 regardless of the radial size of the lower wafer W2.

It is assumed that the non-bonding surface W2 n of the lower wafer W2 issucked and held by the holding pins 42 b 2. In the above description,the second temperature control holding plate 42 b holds the lower waferW2 by suction. However, the present disclosure is not limited thereto.For example, the vacuum pump 42 b 4 and the suction pipe 42 b 3 may beremoved and the lower wafer W2 may be held by mounting.

A second temperature control mechanism 42 b 5 is built in the secondtemperature control holding plate 42 b. For example, a coolant iscirculated through the second temperature control mechanism 42 b 5. Aplurality of proximity pins 42 b 7 capable of supporting the lower waferW2 is provided on the holding surface 42 b 1 of the second temperaturecontrol holding plate 42 b.

In the second temperature control holding plate 42 b configured asabove, the transferred lower wafer W2 is held by the holding pins 42 b2. Subsequently, the holding pins 42 b 2 are moved down until the tipsof the holding pins 42 b 2 are positioned lower than the proximity pins42 b 7. As a result, the lower wafer W2 is supported by the proximitypins 42 b 7. An appropriate gap is secured between the lower wafer W2and the holding surface 42 b 1 of the second temperature control holdingplate 42 b. In this manner, the second temperature control holding plate42 b adjusts the temperature of the lower wafer W2 in a state in whichan appropriate spaced-apart distance between the second temperaturecontrol holding plate 42 b and the lower wafer W2 is maintained.

Although the proximity pins 42 b 7 are used in the second temperaturecontrol holding plate 42 b, the present disclosure is not limitedthereto. For example, the proximity pins 42 b 7 may be removed and thetemperature of the lower wafer W2 may be adjusted by lowering theholding pins 42 b 2 to a position where the holding pins 42 b 2 isappropriately spaced apart from the lower wafer W2, and maintaining theholding pins 42 b 2 at the position.

As the first and second temperature control mechanisms 42 a 5 and 42 b5, it may be possible to use cooling jackets or the like. However, thepresent disclosure is not limited thereto. For example, other types oftemperature control mechanisms such as a heater and the like may beused.

The substrate temperature control device 42 configured as above performstemperature control so that the lower wafer W2 before bonding has ahigher temperature than the temperature of the upper wafer W1 beforebonding. As a result, it is possible to suppress scaling.

Scaling is a phenomenon that, for example, in the bonded laminated waferT, a positional deviation occurs in the horizontal direction at theperipheral edges of the upper wafer W1 and the lower wafer W2, even ifthe central portions of the upper wafer W1 and the lower wafer W2 arealigned with each other. This phenomenon occurs because, as will bedescribed later, when bonding the upper wafer W1 and the lower wafer W2,the central portion W1 a of the upper wafer W1 is lowered toward thecentral portion W2 a of the lower wafer W2 by a pushing member 250 (seeFIG. 16D), whereby the upper wafer W1 is warped and stretched downwardin a convex shape.

Therefore, in the substrate temperature control device 42 according tothis embodiment, the temperature control is performed so that the lowerwafer W2 before bonding has a higher temperature than the temperature ofthe upper wafer W1 before bonding, thereby expanding the lower wafer W2.Thus, it is possible to effectively suppress the horizontal positionaldeviation (scaling) of the peripheral edges of the upper wafer W1 andthe lower wafer W2.

In the above description, the substrate temperature control device 42performs temperature control so that the lower wafer W2 before bondinghas a higher temperature than the temperature of the upper wafer W1before bonding. However, this is illustrative and not limitative. Forexample, the lower wafer W2 and the upper wafer W1 may have the sametemperature.

In the above description, the substrate temperature control device 42controls the temperatures of both the upper wafer W1 and the lower waferW2. However, the present disclosure is not limited thereto. Thetemperature of any one of the upper wafer W1 and the lower wafer W2 maybe controlled.

As described above, the substrate temperature control device 42 isdisposed on the downstream side of the bonding apparatus 41 in the flowdirection of the temperature control air (see FIG. 1). Accordingly, thetemperature environments around the substrate temperature control device42 and the bonding apparatus 41 are similar. Thus, when the upper waferW1 and the lower wafer W2 whose temperatures have been controlled by thesubstrate temperature control device 42 are transferred to the bondingapparatus 41, it is possible to limit influences such as a decrease inthe wafer temperature due to the surrounding temperature. Consequently,it is possible to easily manage the temperatures of the upper wafer W1and the lower wafer W2.

In addition, for example, the transfer device of the related art isconfigured to receive the upper wafer W1 and the lower wafer W2 one at atime from the substrate temperature control device and to transfer theupper wafer W1 and the lower wafer W2 to the bonding apparatus.Therefore, it takes time to transfer a set of the first and secondsubstrates to the bonding apparatus.

Thus, in this embodiment, the substrate temperature control device 42and the transfer device 61 are configured as described above. Therefore,the transfer device 61 can receive two upper and lower wafers W1 and W2together from the substrate temperature control device 42. As a result,in the bonding system 1, the processing time for transferring the upperwafer W1 and the lower wafer W2 to the bonding apparatus 41 can beshortened as compared with the case where the transfer device 61receives the upper wafer W1 and the lower wafer W2 one at a time fromthe substrate temperature control device 42.

Now, an operation in which the above-described transfer device 61receives two upper and lower wafers W1 and W2 together from thesubstrate temperature control device 42 will be described with referenceto FIGS. 8A to 8F. FIGS. 8A to 8F are views for explaining the operationof the transfer device 61 and the substrate temperature control device42. In FIGS. 8A to 8F, the illustration of components other than thecomponents necessary for explanation may be omitted in some cases.

As shown in FIG. 8A, first, the lower wafer W2 before temperaturecontrol is transferred to the substrate temperature control device 42.More specifically, the lower wafer W2 that is sucked and held by thesecond holding part 62 b of the transfer device 61 is transferred tobetween the first temperature control holding plate 42 a and the secondtemperature control holding plate 42 b of the substrate temperaturecontrol device 42.

In the substrate temperature control device 42, the lower wafer W2 issucked and held on the holding pins 42 b 2 by operating the vacuum pump42 b 4 (see FIG. 7) after moving the holding pins 42 b 2 upward.Subsequently, the transfer device 61 stops the vacuum pump 62 b 4 (seeFIG. 6B) to terminate the holding by suction. Then, the transfer device61 is retracted from the substrate temperature control device 42.

Thereafter, as shown in FIG. 8B, the substrate temperature controldevice 42 moves the holding pins 42 b 2 downward. When the lower waferW2 comes into contact with the proximity pins 42 b 7, the vacuum pump 42b 4 is stopped to terminate the holding by suction. Subsequently, theholding pins 42 b 2 are moved down until the tips of the holding pins 42b 2 become lower than the proximity pins 42 b 7. Thus, the lower waferW2 is supported by the proximity pins 42 b 7. As a result, thetemperature of the lower wafer W2 is controlled by the secondtemperature control mechanism 42 b 5.

Next, as shown in FIG. 8C, the upper wafer W1 before temperature controlis transferred to the substrate temperature control device 42.Specifically, the upper wafer W1 sucked and held by the first holdingpart 62 a of the transfer device 61 is transferred between the firsttemperature control holding plate 42 a and the second temperaturecontrol holding plate 42 b of the substrate temperature control device42.

In the substrate temperature control device 42, after the holding pins42 a 2 are moved down, the upper wafer W1 is sucked and held on theholding pins 42 a 2 by operating the vacuum pump 42 a 4 (see FIG. 7).Then, the transfer device 61 stops the vacuum pump 62 a 4 (see FIG. 6B)to terminate the holding by suction. The transfer device 61 is retractedfrom the substrate temperature control device 42. Thereafter, as shownin FIG. 8D, the substrate temperature control device 42 moves theholding pins 42 a 2 upward and brings the upper wafer W1 close to thefirst temperature control holding plate 42 a, whereby the temperature ofthe upper wafer W1 is controlled by the first temperature controlmechanism 42 a 5.

In the state shown in FIG. 8D, the center W2 c of the lower wafer W2held by the second temperature control holding plate 42 b and the centerW1 c of the upper wafer W1 held by the first temperature control holdingplate 42 a are shifted from each other.

In the substrate temperature control device 42, as described above, thetemperature of the lower wafer W2 is controlled to be higher than thetemperature of the upper wafer W1. Therefore, the lower wafer W2 and theupper wafer W1 are transferred in the named order to secure enough timeto raise the temperature of the lower wafer W2. The order in which theupper wafer W1 and the lower wafer W2 are transferred to the substratetemperature control device 42 is not limited thereto. For example, theupper wafer W and the lower wafer W2 may be transferred in the namedorder or may be transferred at the same time.

Next, the first and second holding parts 62 a and 62 b of the transferdevice 61 receive the upper wafer W1 and the lower wafer W2 held andtemperature-controlled by the first and second temperature controlholding plates 42 a and 42 b, at the same time, from the first andsecond temperature control holding plates 42 a and 42 b, and hold theupper wafer W1 and the lower wafer W2 thus received.

Specifically, as shown in FIG. 8E, in the substrate temperature controldevice 42, the holding pins 42 a 2 are moved down to lower the upperwafer W1 to a position where the upper wafer W1 can be received by thefirst holding part 62 a. In the substrate temperature control device 42,the vacuum pump 42 b 4 (see FIG. 7) is operated while moving the holdingpins 42 b 2 upward, so that the holding pins 42 b 2 suck and hold thelower wafer W2 supported by the proximity pins 42 b 7. Thereafter, theholding pins 42 b 2 are further moved upward to raise the lower wafer W2to a position where the lower wafer W2 can be received by the secondholding part 62 b.

Then, the first and second holding parts 62 a and 62 b of the transferdevice 61 are moved between the first temperature control holding plate42 a and the second temperature control holding plate 42 b to receivetwo upper and lower wafers W1 and W2 together. More specifically, thefirst holding part 62 a operates the vacuum pump 62 a 4 (see FIG. 6B) tosuck the upper wafer W1 and the second holding part 62 b operates thevacuum pump 62 b 4 (see FIG. 6B) to suck the lower wafer W2, therebyreceiving two upper and lower wafers W1 and W2 together. At this time,the second holding part 62 b holds the lower wafer W2 with the center W2c thereof shifted from the center W1 c of the upper wafer W1.

Subsequently, the substrate temperature control device 42 stops thevacuum pumps 42 a 4 and 42 b 4 (see FIG. 7) to terminate the holding bysuction. Thereafter, as shown in FIG. 8F, the first and second holdingparts 62 a and 62 b of the transfer device 61 are retracted from thesubstrate temperature control device 42 and transfer the upper wafer W1and the lower wafer W2 held thereon to the bonding apparatus 41. Inaddition, in the substrate temperature control device 42, the holdingpins 42 a 2 are moved up and the holding pins 42 b 2 are moved down sothat they return to the initial positions, respectively.

As described above, in this embodiment, the transfer device 61 receivesthe upper wafer W1 and the lower wafer W2 together from the substratetemperature control device 42 at the same time. Therefore, theprocessing time for transferring the upper wafer W1 and the lower waferW2 to the bonding apparatus 41 can be shortened as compared with thecase where the upper wafer W1 and the lower wafer W2 are received one ata time from the substrate temperature control device 42.

Subsequently, in the bonding system 1, both of the upper wafer W1 andthe lower wafer W2 are transferred and delivered to the bondingapparatus 41 by the transfer device 61. At this time, in order for thetransfer device 61 to deliver the upper wafer W1 and the lower wafer W2to appropriate positions in the bonding apparatus 41, the positiondetecting parts 70 a to 70 d detect the positions of the upper wafer W1and the lower wafer W2 held by the transfer device 61.

As described above, the position detecting parts 70 a to 70 d aredisposed in a direction perpendicular to the surfaces of the upper waferW1 and the lower wafer W2 held as above (see FIG. 6B). Therefore, forexample, when the centers W1 c and W2 c of the upper wafer W1 and thelower wafer W2 are at the same position in a plan view, the lower waferW2 is hidden by the upper wafer W1. Thus, the position detecting parts70 a to 70 d cannot detect the position of the lower wafer W2.

Therefore, in this embodiment, as described above, the second holdingpart 62 b holds the lower wafer W2 in a state in which the center W2 cthereof is shifted from the center W1 c of the upper wafer W1. As aresult, the position detecting parts 70 a to 70 d can detect thepositions of the upper wafer W1 and the lower wafer W2.

FIG. 9 is a view for explaining the detection of the positions of theupper wafer W1 and the lower wafer W2 by the position detecting parts 70a to 70 d. Furthermore, FIG. 9 is a schematic plan view of the transferdevice 61.

As shown in FIG. 9, the lower wafer W2 is held in a state in which thecenter W2 c thereof is shifted from the center W1 c of the upper waferW1. Therefore, in the lower wafer W2, at least a portion of theperipheral edge of the lower wafer W2 is exposed from the upper wafer W1in a plan view.

The fact that the center W2 c of the lower wafer W2 is shifted from thecenter W1 c of the upper wafer W1 in the Y axis positive direction canbe noted from the positional relationship between the first temperaturecontrol holding plate 42 a and the second temperature control holdingplate 42 b. Therefore, among the position detecting parts 70 a to 70 d,the position detecting parts 70 a and 70 c arranged in the Y axispositive direction detect the position (points Pa2 and Pb2) of theperipheral edge of the lower wafer W2, and the position detecting parts70 b and 70 d arranged in the Y axis negative direction detect theposition (points Pa1 and Pb1) of the peripheral edge of the upper waferW1.

In the position detecting parts 70 a and 70 c, the position of theperipheral edge at the points Pa2 and Pb2 are acquired with respect tothe lower wafer W2. Thus, the position of the held lower wafer W2 isdetected on the basis of the information on the position of theperipheral edge and the radius of the lower wafer W2 already detected.Similarly, in the position detecting parts 70 b and 70 d, the positionof the peripheral edge at the points Pa1 and Pb1 are acquired withrespect to the upper wafer W1. Thus, the position of the held upperwafer W1 is detected on the basis of the information on the position ofthe peripheral edge and the radius of the upper wafer W1 alreadydetected.

As described above, the position detecting parts 70 a to 70 d detect theperipheral edge of the upper wafer W1 and detect the peripheral edge ofthe lower wafer W2 exposed from the upper wafer W1 in a plan view due tothe shift of the center W2 c from the center W1 c of the upper wafer W1.The position detecting parts 70 a to 70 d detect the positions of theupper wafer W1 and the lower wafer W2 based on the detected peripheraledge of the upper wafer W1 and the detected portion of the peripheraledge of the lower wafer W2.

As a result, in this embodiment, even when the transfer device 61receives two upper and lower wafers W1 and W2 from the substratetemperature control device 42, it is possible to accurately detect thepositions of the upper wafer W1 and the lower wafer W2 held by thetransfer device 61. Consequently, it is possible to deliver the upperwafer W1 and the lower wafer W2 to the bonding apparatus 41 atappropriate positions.

As described above, in the substrate temperature control device 42, thesecond temperature control holding plate 42 b is disposed to hold thelower wafer W2 in a state in which the center W2 c thereof is shiftedfrom the center W1 c of the upper wafer W1 held by the first temperaturecontrol holding plate 42 a. Thus, the transfer device 61 can easilyreceive the upper wafer W1 and the lower wafer W2 from the substratetemperature control device 42 in a state in which the centers W1 c andW2 c are shifted from each other.

<2. Configuration of Bonding Apparatus>

Next, the configuration of the bonding apparatus 41 will be describedwith reference to FIGS. 10 to 15. FIG. 10 is a schematic plan viewshowing the configuration of the bonding apparatus 41, and FIG. 11 is aschematic side view thereof. FIG. 12 is a schematic side view showingthe internal configuration of the bonding apparatus 41.

As shown in FIG. 10, the bonding apparatus 41 includes a processingcontainer 190 capable of hermetically sealing the interior thereof. Aloading/unloading port 191 for the upper wafer W1, the lower wafer W2and the laminated wafer T is formed on the side surface of theprocessing container 190 on the side of the transfer region 60. Anopening/closing shutter 192 is provided at the loading/unloading port191.

As shown in FIG. 11, an upper chuck 230 and a lower chuck 231 areprovided inside the processing container 190. The upper chuck 230 sucksand holds the upper wafer W1 from above. The lower chuck 231 is providedbelow the upper chuck 230 to suck and hold the lower wafer W2 frombelow.

As shown in FIG. 11, the upper chuck 230 is supported by a supportmember 280 provided on the ceiling surface of the processing container190.

In the support member 280, an upper imaging part 281 (see FIG. 12) isprovided for capturing an image of the bonding surface W2 j of the lowerwafer W2 held by the lower chuck 231. The upper imaging part 281 isprovided adjacent to the upper chuck 230.

As shown in FIGS. 10, 11 and 12, the lower chuck 231 is supported by afirst lower chuck moving part 290 provided below the lower chuck 231.The first lower chuck moving part 290 moves the lower chuck 231 in thehorizontal direction (Y axis direction) as described later. Furthermore,the first lower chuck moving part 290 is configured to be able to movethe lower chuck 231 in the vertical direction and to be able to rotatethe lower chuck 231 about the vertical axis.

In the first lower chuck moving part 290, there is provided a lowerimaging part 291 for capturing an image of the bonding surface W1 j ofthe upper wafer W1 held by the upper chuck 230. The lower imaging part291 is provided adjacent to the lower chuck 231.

As shown in FIGS. 10, 11 and 12, the first lower chuck moving part 290is attached to a pair of rails 295 and 295 provided on the lower surfaceside of the first lower chuck moving part 290 and extending in thehorizontal direction (Y axis direction). The first lower chuck movingpart 290 is configured to be movable along the rails 295 and 295.

The rails 295 and 295 are provided in the second lower chuck moving part296. The second lower chuck moving part 296 is attached to a pair ofrails 297 and 297 provided on the lower surface side of the second lowerchuck moving part 296 and extending in the horizontal direction (X axisdirection). The second lower chuck moving part 296 is configured to bemovable along the rails 297 and 297, namely to move the lower chuck 231in the horizontal direction (X axis direction). The rails 297 and 297are provided on a mounting table 298 provided on the bottom surface ofthe processing container 190.

Next, the configurations of the upper chuck 230 and the lower chuck 231will be described with reference to FIGS. 13 to 15. FIG. 13 is aschematic side view showing the configurations of the upper chuck 230and the lower chuck 231. FIG. 14 is a schematic plan view of the upperchuck 230 as viewed from below, and FIG. 15 is a schematic plan view ofthe lower chuck 231 as viewed from above.

As shown in FIG. 13, the upper chuck 230 is partitioned into a pluralityof, for example, three regions 230 a, 230 b and 230 c. As shown in FIG.14, these regions 230 a, 230 b and 230 c are provided in this order fromthe central portion of the upper chuck 230 toward the peripheral edgeportion (outer peripheral portion) thereof. The region 230 a has acircular shape in a plan view, and the regions 230 b and 230 c have anannular shape in a plan view.

As shown in FIG. 13, suction pipes 240 a, 240 b and 240 c for suckingand holding the upper wafer W1 are provided independently in therespective regions 230 a. 230 b and 230 c. Different vacuum pumps 241 a.241 b and 241 c are connected to the suction pipes 240 a, 240 b and 240c, respectively. In this manner, the upper chuck 230 is configured so asto be able to set the vacuum drawing of the upper wafer W1 for each ofthe regions 230 a, 230 b and 230 c.

Further, the upper chuck 230 is provided with a plurality of holdingpins 245 that can be moved up and down in the vertical direction. Avacuum pump 246 is connected to the holding pins 245. That is to say,the holding pins 245 can hold the upper wafer W1 through vacuum suctionby the operation of the vacuum pump 246.

Accordingly, in the upper chuck 230, for example, the holding pins 245suck and receive the upper wafer W1 in a state in which the holding pins245 protrude from the holding surface. Thereafter, the holding pins 245are moved upward to bring the upper wafer W1 into contact with theholding surface. Subsequently, in the upper chuck 230, the vacuum pumps241 a, 241 b and 241 c are operated to suck and hold the upper wafer W1in the regions 230 a, 230 b and 230 c as shown in FIG. 11.

A through-hole 243 penetrating the upper chuck 230 in the thicknessdirection is formed in the central portion of the upper chuck 230. Thecentral portion of the upper chuck 230 corresponds to the centralportion W1 a of the upper wafer W1 sucked and held by the upper chuck230. A pushing pin 251 of a pushing member 250 to be described later isinserted into the through-hole 243.

On the upper surface of the upper chuck 230, a pushing member 250 forpushing the central portion of the upper wafer W1 is provided. Thepushing member 250 has a cylinder structure and includes a pushing pin251 and an outer cylinder 252 serving as a guide when the pushing pin251 moves up and down. The pushing pin 251 can be vertically moved upand down through the through-hole 243 by, for example, a driving part(not shown) incorporating a motor therein. At the time of bonding theupper wafer W1 and the lower wafer W2 as described later, the pushingmember 250 can press the central portion W1 a of the upper wafer W1 andthe central portion W2 a of the lower wafer W2 against each other.

As shown in FIG. 15, the lower chuck 231 is partitioned into a pluralityof, for example, two regions 231 a and 231 b. These regions 231 a and231 b are provided in this order from the central portion of the lowerchuck 231 toward the peripheral edge portion thereof. The region 231 ahas a circular shape in a plan view, and the region 231 b has an annularshape in a plan view.

As shown in FIG. 13, suction pipes 260 a and 260 b for sucking andholding the lower wafer W2 are provided independently in the respectiveregions 231 a and 231 b. Different vacuum pumps 261 a and 261 b areconnected to the suction pipes 260 a and 260 b, respectively. Asdescribed above, the lower chuck 231 is configured so as to be able toset the vacuum drawing of the lower wafer W2 for each of the regions 231a and 231 b.

Further, the lower chuck 231 is provided with a plurality of holdingpins 265 capable of moving up and down in the vertical direction. In thelower chuck 231, for example, the holding pins 265 mount and receive thelower wafer W2 in a state in which the holding pins 265 protrude fromthe holding surface. Thereafter, the holding pins 265 are moved down tobring the lower wafer W2 into contact with the holding surface.Subsequently, in the lower chuck 231, the vacuum pumps 261 a and 261 bare operated to suck and hold the lower wafer W2 in the respectiveregions 231 a and 231 b as shown in FIG. 13. In the above description,the holding pins 265 hold the lower wafer W2 by mounting. However, thepresent disclosure is not limited thereto. Similar to the holding pins245 of the upper chuck 230, the holding pins 265 may hold the lowerwafer W2 by suction.

In the peripheral edge portion of the lower chuck 231, stopper members263 for preventing the upper wafer W1, the lower wafer W2 and thelaminated wafer T from jumping out or slipping off from the lower chuck231 are provided at a plurality of locations, for example, at fivelocations.

<3. Wafer Position Adjusting and Bonding Operation in Bonding Apparatus>

Next, the position adjustment of the upper wafer W1 and the lower waferW2 and the bonding operation of the upper wafer W1 and the lower waferW2 in the bonding apparatus 41 configured as above will be specificallydescribed. FIGS. 16A to 16H are operation explanation views of thebonding apparatus 41.

It is assumed that the upper wafer W1 and the lower wafer W2 shown inFIGS. 16A to 16H have undergone the modifying process and thehydrophilizing process on the bonding surfaces W1 j and W2 j,respectively. In addition, it is assumed that the non-bonding surfaceWin of the upper wafer W1 is sucked and held by the upper chuck 230 andthe non-bonding surface W2 n of the lower wafer W2 is sucked and held bythe lower chuck 231.

Then, the upper wafer W1 held by the upper chuck 230 and the lower waferW2 held by the lower chuck 231 are subjected to horizontal positionadjustment.

As shown in FIG. 16A, a predetermined plurality of, for example, threereference points A1 to A3 are formed on the bonding surface W1 j of theupper wafer W1. Similarly, a predetermined plurality of, for example,three reference points B1 to B3 are formed on the bonding surface W2 jof the lower wafer W2. As the reference points A1 to A3 and B1 to B3,predetermined patterns formed on the upper wafer W1 and the lower waferW2 are used, respectively. The number of reference points can bearbitrarily set.

First, as shown in FIG. 16A, the horizontal positions of the upperimaging part 281 and the lower imaging part 291 are adjusted.Specifically, the lower chuck 231 is horizontally moved by the firstlower chuck moving part 290 and the second lower chuck moving part 296so that the lower imaging part 291 is positioned substantially below theupper imaging part 281. Then, a common target X is confirmed by theupper imaging part 281 and the lower imaging part 291. The horizontalposition of the lower imaging part 291 is finely adjusted so that thehorizontal positions of the upper imaging part 281 and the lower imagingpart 291 are aligned with each other.

Next, as shown in FIG. 16B, after the lower chuck 231 is movedvertically upward by the first lower chuck moving part 290, thehorizontal positions of the upper chuck 230 and the lower chuck 231 areadjusted.

More specifically, while moving the lower chuck 231 in the horizontaldirection by the first lower chuck moving part 290 and the second lowerchuck moving part 296, the reference points B1 to B3 of the bondingsurface W2 j of the lower wafer W2 are imaged using the upper imagingpart 281. At the same time, while moving the lower chuck 231 in thehorizontal direction, the reference points A1 to A3 of the bondingsurface W1 j of the upper wafer W1 are sequentially imaged using thelower imaging part 291. FIG. 16B shows a state in which the referencepoint B1 of the lower wafer W2 is imaged by the upper imaging part 281and the reference point A1 of the upper wafer W1 is imaged by the lowerimaging part 291.

The captured image data is outputted to the control device 100. Based onthe image data captured by the upper imaging part 281 and the image datacaptured by the lower imaging part 291, the control device 100 causesthe first and second lower chuck moving parts 290 and 296 to adjust thehorizontal position of the lower chuck 231 so that the reference pointsA1 to A3 of the upper wafer W1 and the reference points B1 to B3 of thelower wafer W2 are aligned with each other. Thus, the horizontalpositions of the upper chuck 230 and the lower chuck 231 are adjusted,and the horizontal positions of the upper wafer W1 and the lower waferW2 are adjusted.

Next, as shown in FIG. 16C, the lower chuck 231 is vertically movedupward by the first lower chuck moving part 290, whereby the verticalpositions of the upper chuck 230 and the lower chuck 231 are adjusted,and the vertical positions of the upper wafer W1 held by the upper chuck230 and the lower wafer W2 held by the lower chuck 231 are adjusted. Atthis time, the gap between the bonding surface W2 j of the lower waferW2 and the bonding surface W1 j of the upper wafer W1 is a predetermineddistance, for example, 80 μm to 200 μm.

With such a configuration, it is possible to adjust the horizontalpositions and the vertical positions of the upper wafer W1 and the lowerwafer W2 with high accuracy.

FIG. 16D shows the states of the upper chuck 230, the upper wafer W1,the lower chuck 231 and the lower wafer W2 after the adjustment of thehorizontal positions and the vertical positions described above iscompleted. As shown in FIG. 16D, the upper wafer W1 is vacuum-drawn andheld in all the regions 230 a, 230 b and 230 c of the upper chuck 230,and the lower wafer W2 is also vacuum-drawn and held in all the regions231 a and 231 b of the lower chuck 231.

Next, a bonding process is performed in which the upper wafer W1 and thelower wafer W2 are bonded by an intermolecular force. Specifically, inthe bonding process, the operation of the vacuum pump 241 a is stopped,and the vacuum drawing of the upper wafer W1 from the suction pipe 240 ain the region 230 a is stopped as shown in FIG. 16E. At this time, inthe regions 230 b and 230 c, the upper wafer W1 is vacuum-drawn, suckedand held. Thereafter, by moving down the pushing pin 251 of the pushingmember 250, the upper wafer W1 is lowered while pressing the centralportion W1 a of the upper wafer W1. At this time, a load of, forexample, 200 g, is applied to the pushing pin 251 such that the pushingpin 251 moves 70 μm in the absence of the upper wafer W1. Then, thecentral portion W1 a of the upper wafer W1 and the central portion W2 aof the lower wafer W2 are brought into contact with each other andpressed against each other by the pushing member 250.

As a result, bonding is started between the central portion W1 a of thepressed upper wafer W1 and the central portion W2 a of the lower waferW2 (bold line portion in FIG. 16E). Since the bonding surface W1 j ofthe upper wafer W1 and the bonding surface W2 j of the lower wafer W2are respectively modified, a van der Waals force (intermolecular force)is first generated between the bonding surfaces W1 j and W2 j. Thus, thebonding surfaces W1 j and W2 j are bonded together. Furthermore, sincethe bonding surface W1 j of the upper wafer W and the bonding surface W2j of the lower wafer W2 are made hydrophilic, the hydrophilic groupsbetween the bonding surfaces W1 j and W2 j are hydrogen-bonded. Thus,the bonding surfaces W1 j and W2 j are strongly bonded together.

Thereafter, as shown in FIG. 16F, the operation of the vacuum pump 241 bis stopped in a state in which the central portion W1 a of the upperwafer W1 and the central portion W2 a of the lower wafer W2 are pressedby the pushing member 250, whereby the vacuum drawing of the upper waferW1 from the suction pipe 240 b in the region 230 b is stopped.

As a result, the upper wafer W1 held in the region 230 b drops onto thelower wafer W2. Thereafter, the operation of the vacuum pump 241 c isstopped, whereby the vacuum drawing of the upper wafer W1 from thesuction pipe 240 c in the region 230 c is stopped. In this way, thevacuum drawing of the upper wafer W1 is stopped stepwise from thecentral portion W a of the upper wafer W1 toward the peripheral edgeportion W1 b. Thus, the upper wafer W1 drops down and comes into contactwith the lower wafer W2 in a stepwise manner. The aforementioned bondingdue to the van der Waals force and the hydrogen bond between the bondingsurfaces W1 j and W2 j is sequentially spread from the central portionW1 a toward the peripheral edge portion W1 b.

In this way, as shown in FIG. 16G, the bonding surface W1 j of the upperwafer W1 and the bonding surface W2 j of the lower wafer W2 make contactwith each other over each of the surfaces in their entirety, whereby theupper wafer W1 and the lower wafer W2 are bonded together.

Thereafter, as shown in FIG. 16H, the pushing member 250 is moved up tothe upper chuck 230. Further, in the lower chuck 231, the vacuum drawingof the lower wafer W2 from the suction pipes 260 a and 260 b is stopped,whereby the suction holding of the lower wafer W2 by the lower chuck 231is canceled. As a result, the bonding process in the bonding apparatus41 is completed.

<4. Specific Operation of Bonding System)>

Next, a specific operation of the bonding system 1 configured as abovewill be described with reference to FIG. 17. FIG. 17 is a flowchartshowing a part of the processing procedure of the processes executed bythe bonding system 1. The various processes shown in FIG. 17 areexecuted under the control of the control device 100.

First, a cassette C1 accommodating a plurality of upper wafers W1, acassette C2 accommodating a plurality of lower wafers W2, and an emptycassette C3 are mounted on the predetermined mounting plates 11 of theloading/unloading station 2. Thereafter, the upper wafer W1 in thecassette C1 is taken out by the transfer device 22 and is transferred tothe transition 53 of the third processing block G3 of the processingstation 3.

Next, the upper wafer W1 is transferred to the load lock chamber 31 ofthe first processing block G1 by the transfer device 61 and is mountedon the transition 31 a 1, whereby the delivery of the upper wafer W1 isperformed (step S101). Next, after the gate valve 36 a is closed, thevacuum pump 31 c is operated, whereby the load lock chamber 31 isdepressurized into a depressurized atmosphere (step S102).

Next, the upper wafer W1 is transferred from the load lock chamber 31 tothe surface modifying apparatus 33 by the modifying transfer device 32 aof the transfer chamber 32. In the surface modifying apparatus 33, anoxygen gas as a process gas is excited into plasma and ionized under adepressurized atmosphere. The oxygen ions are irradiated onto thebonding surface W1 j of the upper wafer W1, whereby the bonding surfaceW1 j is plasma-processed. As a result, the bonding surface W1 j of theupper wafer W1 is modified (step S103).

Next, the upper wafer W1 is transferred from the surface modifyingapparatus 33 to the load lock chamber 31 by the modifying transferdevice 32 a and is mounted on the transition 31 a 2. Then, the load lockchamber 31 is switched from the depressurized atmosphere to anatmospheric pressure atmosphere by opening the gate valve 36 a, and theupper wafer W1 is delivered (step S104). As described above, the loadlock chamber 31 is set to an atmospheric pressure atmosphere. However,the transfer chamber 32 and the surface modifying apparatus 33 are keptin the depressurized atmosphere.

Next, the upper wafer W1 is transferred from the load lock chamber 31 tothe surface hydrophilizing apparatus 34 by the transfer device 61. Inthe surface hydrophilizing apparatus 34, while rotating the upper waferW1 held by the spin chuck, pure water is supplied onto the upper waferW1. Then, the supplied pure water diffuses on the bonding surface W1 jof the upper wafer W1. A hydroxyl group (silanol group) adheres to thebonding surface W1 j of the upper wafer W1 modified in the surfacemodifying apparatus 33, whereby the bonding surface W1 j is renderedhydrophilic. In addition, the bonding surface W1 j of the upper wafer W1is cleaned with the pure water (step S105).

Next, the hydrophilized upper wafer W1 is transferred to the positionadjusting device 51 by the transfer device 61. Then, the horizontalorientation of the upper wafer is adjusted by the position adjustingdevice 51 (step S106).

Thereafter, the front and back surfaces of the upper wafer W1 areinverted by the base inverting part 51 d of the position adjustingdevice 51, whereby the bonding surface W1 j serves as a lower surface(step S107). Next, the upper wafer W1 having the bonding surface W1 j asa lower surface is transferred to the substrate temperature controldevice 42 by the transfer device 61. The upper wafer W1 is sucked andheld by the first temperature control holding plate 42 a of thesubstrate temperature control device 42. As a result, the temperature ofthe upper wafer W1 is controlled (step S108).

The above-described processes of steps S101 to S106 and S108 are alsoperformed with respect to the lower wafer W2. First, the lower wafer W2in the cassette C2 is taken out by the transfer device 22 and istransferred to the transition 54 of the processing station 3.

Next, the lower wafer W2 is transferred to the load lock chamber 31 bythe transfer device 61, whereby the delivery of the lower wafer W2 isperformed (step S109). Subsequently, the load lock chamber 31 isdepressurized into a depressurized atmosphere (step S110).

Next, the lower wafer W2 is transferred from the load lock chamber 31 tothe surface modifying apparatus 33 by the modifying transfer device 32a, and the bonding surface W2 j is reformed (step S111). Then, the lowerwafer W2 is transferred from the surface modifying apparatus 33 to theload lock chamber 31 by the modifying transfer device 32 a. The loadlock chamber 31 is switched from the depressurized atmosphere to theatmospheric pressure atmosphere, and the delivery of the lower wafer W2is performed (step S112).

Next, the lower wafer W2 is transferred from the load lock chamber 31 tothe surface hydrophilizing apparatus 34 by the transfer device 61. Thebonding surface W2 j is made hydrophilic and is cleaned (step S113).

Next, the hydrophilized lower wafer W2 is transferred to the positionadjusting device 51 by the transfer device 61, and the horizontalorientation of the lower wafer W2 is adjusted (step S114). At this time,the lower wafer W2 is in a state in which the bonding surface W2 jserves as an upper surface.

Next, the lower wafer W2 having the bonding surface W2 j as an uppersurface is transferred to the substrate temperature control device 42.The lower wafer W2 is sucked and held by the second temperature controlholding plate 42 b, and the temperature of the lower wafer W2 iscontrolled (step S115). In the substrate temperature control device 42,for example, the lower wafer W2 is controlled to have a highertemperature than the upper wafer W1.

In the above-described steps S101 to S106 and S109 to S115, the transferof the upper wafer W1 and the lower wafer W2 by the transfer device 61is performed by the second holding part 62 b. In the steps S107 andS108, the transfer of the upper wafer W1, inverted so that the bondingsurface W1 j serves as a lower surface, is performed by the firstholding part 62 a. However, the present disclosure is not limited tothereto.

Subsequently, the transfer device 61 receives the upper wafer W1 and thelower wafer W2 from the substrate temperature control device 42 at thesame time, i.e., simultaneously (step S116). Then, the positiondetecting parts 70 a to 70 d detect the positions of the upper wafer Wand the lower wafer W2 held by the transfer device 61 (step S117). Next,the transfer device 61 transfers the upper wafer W1 and the lower waferW2 to the bonding apparatus 41 (step S118).

Next, the first holding part 62 a moves the upper wafer W1 to anappropriate position below the upper chuck 230 based on the position ofthe upper wafer W1 detected earlier. Then, the upper wafer W1 is suckedand held by the upper chuck 230 (step S119).

Next, the second holding part 62 b moves the lower wafer W2 to anappropriate position above the lower chuck 231 based on the detectedposition of the lower wafer W2 and causes the lower wafer W2 to besucked and held by the lower chuck 231 (step S120).

Subsequently, in the bonding apparatus 41, the horizontal positionadjustment of the upper wafer W1 held by the upper chuck 230 and thelower wafer W2 held by the lower chuck 231 is performed (step S121).Next, the vertical position adjustment of the upper wafer W1 held by theupper chuck 230 and the lower wafer W2 held by the lower chuck 231 isperformed (step S122).

Next, the central portion W1 a of the upper wafer W1 and the centralportion W2 a of the lower wafer W2 are brought into contact with eachother and pressed against each other by the pushing member 250 (stepS123). Then, the upper wafer W1 and the lower wafer W2 are bonded by anintermolecular force (step S124).

The laminated wafer T in which the upper wafer W1 and the lower wafer W2are bonded is transferred to the transition 54 by the second holdingpart 62 b of the transfer device 61 (step S125). Thereafter, thelaminated wafer T is transferred to the cassette C3 on a predeterminedmounting plate 11 by the transfer device 22 of the loading/unloadingstation 2. Thus, a series of processes is completed.

As described above, the bonding system 1 according to the embodimentincludes the transfer device 61 configured to transfer the upper waferW1 and the lower wafer W2 to the bonding apparatus 41 that bonds theupper wafer W1 and the lower wafer W2. Furthermore, the bonding system 1includes the first temperature control holding plate 42 a configured tohold the upper wafer W1 from the upper surface side, and the secondtemperature control holding plate 42 b provided under the firsttemperature control holding plate 42 a and configured to hold the lowerwafer W2 from the lower surface side so that the lower wafer W2 facesthe upper wafer W1.

The transfer device 61 includes the first holding part 62 a capable ofholding the upper wafer W1 from the upper surface side, and the secondholding part 62 b provided below the first holding part 62 a and capableof holding the lower wafer W2 from the lower surface side so that thelower wafer W2 faces the upper wafer W1. The first and second holdingparts 62 a and 62 b receive the upper wafer W1 and the lower wafer W2held by the first and second temperature control holding plates 42 a and42 b, at the same time, from the first and second temperature controlholding plates 42 a and 42 b, and hold the upper wafer W1 and the lowerwafer W2. Thus, it is possible to shorten the processing time fortransferring the upper wafer W1 and the lower wafer W2 to the bondingapparatus 41.

In the above-described embodiment, one load lock chamber 31 is provided.However, the present disclosure is not limited thereto. Two or more loadlock chambers may be provided. In addition, the number of thetransitions 31 a 1 and 31 a 2 in the load lock chamber 31 may be one orthree or more.

In the bonding system 1 described above, the substrate temperaturecontrol device 42 is disposed adjacent to the bonding apparatus 41.However, the present disclosure is not limited thereto. For example, thesubstrate temperature control device 42 may be disposed at anotherlocation such as the third processing block G3 or the like. Furthermore,in the bonding system 1, the substrate temperature control device 42 maybe removed.

In the above description, the upper wafer W1 or the like is held byvacuum suction or mounting. However, the present disclosure is notlimited thereto. For example, a mechanical chuck for mechanicallyholding a substrate or an electrostatic chuck for holding a substratewith an electrostatic attraction force may be appropriately used.

According to the present disclosure in some embodiments, it is possibleto shorten a processing time for transferring first and secondsubstrates to a bonding apparatus.

Additional effects and modifications can be easily derived by thoseskilled in the art. Thus, the broader aspects of the present disclosureare not limited to the specific details and representative embodimentsshown and described as above. Accordingly, various modifications areavailable without departing from the spirit or scope of the generalinventive concept as defined by the appended claims and theirequivalents.

What is claimed is:
 1. A bonding system comprising: a first holding plate including a plurality of first holding pins which are configured to move upward and downward and are connected to a first vacuum pump, and configured to hold a first substrate from an upper surface side by the plurality of first holding pins through vacuum suction of the first vacuum pump; a second holding plate including a plurality of second holding pins which are configured to move upward and downward and are connected to a second vacuum pump, disposed below the first holding plate, and configured to hold a second substrate from a lower surface side by the plurality of second holding pins through vacuum suction of the second vacuum pump so that the second substrate faces the first substrate; a substrate transfer device including: a first holder including a lower surface configured to hold an upper surface of the first substrate; a second holder disposed below the first holder and including an upper surface configured to hold a lower surface of the second substrate so that an upper surface of the second substrate faces a lower surface of the first substrate; and a driving part connected to both the first holder and the second holder and configured to integrally move the first holder and the second holder in a vertical direction, a horizontal direction, and about a vertical axis, wherein the first holder and the second holder maintain the upper surface of the second substrate facing the lower surface of the first substrate, a controller programmed to perform a process including: while the plurality of first holding pins are moved downward to separate the first substrate from the first holding plate, and the plurality of second holding pins are moved upward to separate the second substrate from the second holding plate, transferring the first substrate held by the plurality of first holding pins of the first holding plate through vacuum suction of the first vacuum pump and the second substrate held by the plurality of second holding pins of the second holding plate through vacuum suction of the second vacuum pump, at the same time, from the first holding plate and the second holding plate to the first holder and the second holder, respectively, and holding, the first substrate and the second substrate on the first holder and the second holder, respectively.
 2. The bonding system of claim 1, further comprising a position detecting part disposed in a direction perpendicular to a surface of the first substrate held by the first holder and a surface of the second substrate held by the second holder, and configured to detect a position of the first substrate and a position of the second substrate, wherein the second holder is configured to hold the second substrate in a state in which a center of the second substrate is shifted from a center of the first substrate, and the position detecting part is configured to detect a peripheral edge of the first substrate, to detect a portion of a peripheral edge of the second substrate exposed from the first substrate in a plan view due to the center of the second substrate being shifted from the center of the first substrate, and to detect the position of the first substrate and the position of the second substrate based on the detected peripheral edge of the first substrate and the detected portion of the peripheral edge of the second substrate.
 3. The bonding system of claim 2, wherein the second holding plate is configured to hold the second substrate before being held by the second holder, in a state in which the center of the second substrate is shifted from the center of the first substrate held by the first holding plate.
 4. The bonding system of claim 3, wherein at least one of the first holding plate and the second holding plate includes a temperature control mechanism configured to control a temperature of the first substrate or a temperature of the second substrate.
 5. The bonding system of claim 3, wherein the second holding plate is configured to hold the second substrate by vacuum suction.
 6. The bonding system of claim 1, wherein the process further includes, when the first substrate and the second substrate are unloaded from the first holding plate and the second holding plate, maintaining the first substrate and the second substrate at a predetermined distance smaller than a radius of the first substrate and smaller than a radius of the second substrate. 